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Nieu Bethesda Housing Development

Draft-Specialist Wetland Evaluation of the Proposed Nieu Bethesda Housing Development Site

Aurecon Port Elizabeth Office

14 September 2018

Revision: 1

Reference: 110795

Project 110795 File Nieu Bethesda Housing Development Wetland Report_REV02_ML.docx 14 September 2018 Revision 1

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Report title Draft-Specialist Wetland Evaluation of the Proposed Nieu Bethesda Housing Development Site

Document ID Project number 110795

File path P:\Projects\110795 Nieu Bethesda Housing Project\ 02 PRJ Man\6 HSE ENV\09_Applications & Reports\WULA\Supporting Docum ents

Client Aurecon Port Elizabeth Office

Client contact Ivor Berrington Client reference Nieu Bethesda Housing Development

Rev Date Revision details/status

Author Reviewer Verifier (if required)

Approver

0 10/09/2018 Draft Margaret Lowies Louise Palmer Theuns Duvenhage

Current revision 1

Approval

Author signature Approver signature

Name Margaret Lowies Name Theuns Duvenhage

Title Environmental Practitioner, Aurecon

Title Technical Director - Environmental & Advisory, Aurecon


Indemnity and conditions relating to this report The findings, results, observations, conclusions and recommendations given in this report are based on the author’s best scientific and professional knowledge and experience, as well as available information. The report is based on recognised survey and assessment techniques which are limited by time and budgetary constraints relevant to the type and level of investigation undertaken. Aurecon reserves the right to modify aspects of the report including the recommendations if and when new information may become available from on-going research or further work in this field, or pertaining to this investigation. Although Aurecon exercised due care and diligence in rendering services and preparing documents, they accept no liability, and the client, by receiving this document, indemnifies Aurecon against all actions, claims, demands, losses, liabilities, costs, damages and expenses arising from or in connection with services rendered, directly or indirectly by Aurecon and by the use of the information contained in this document. This report must not be altered or added to without the prior written consent of the author. This also refers to electronic copies of this report which are supplied for the purposes of inclusion as part of other reports, including main reports. Similarly, any recommendations, statements or conclusions drawn from or based on this report must make reference to this report. If these form part of a main report relating to this investigation or report, this report must be included in its entirety as an appendix or separate section to the main report.

Project 110795 File Nieu Bethesda Housing Development Wetland Report_REV02_ML.docx

14 September 2018 Revision 1

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Contents 1 Introduction 1

1.1 Background 1

1.2 Proposed project 1

1.3 Scope of Study 1

2 Assumptions and limitations 3

3 Methodology 4

3.1 Overall approach and philosophy to this study 4

3.2 Wetland Delineation 4

3.3 Wetland evaluation 5

4 Study area and site characteristics 7

4.1 General description 7

4.2 Geology 7

4.3 Climate 7

4.4 Surface water 8

4.5 Groundwater 9

4.6 Landcover 9

5 Results 11

5.1 Wetland/site characteristics 11

5.2 Present Ecological State 15

5.3 Ecological importance and sensitivity 15

5.4 Impact assessment 17

6 Summarising discussion of findings 20

7 Recommendations 22

8 References 23


14 September 2018 Revision 1 Page ii

List of tables

Figure 1: Proposed development layout 2 Figure 2: Cross section through a wetland, indicating how the soil wetness and vegetation indicators

change as one moves along a gradient of decreasing wetness from the middle to the

edge of the wetland (DWAF, 2005). 5 Figure 3: Long-term climatic data for Nieu-Bethesda (www.climate-data.org) 7 Figure 4: NFEPA (2011) Fish Sanctuary classifications for the study area 8 Figure 5: Wetland ins study area based on NFEPA (2011) data 9 Figure 6: Land cover in the immediate study area 10 Figure 7: Typical view of the wetland catchment, showing short, sparse vegetation growth, steep

slopes and rocky surface 10 Figure 8: View of the wetland from the southern edge looking north. In the foreground is the seasonal

and permanent zone wetland mosaic indicated by the green vegetation and Juncus

vegetation 14 Figure 9: The deep cut-off channel skirting the eastern low-cost housing area is 14 Figure 10: Weir wall in the Gats River looking west 15 Figure 11: Straightened and canalised tributary upstream of its confluence with the Gats River 15 Figure 12: 1m Contour map (generated from Google Earth elevation data via QGIS) showing the

topography of the study area in spectral colour range (blues depicting lower elevations) 16 Figure 13: Location of trail pits for Geotechnical investigation 16 Figure 14: Trial pit 9 illustrating typical soil conditions and perched water table 18 Figure 15: Overview of study area 1 Figure 16:Catchment impacts 15 Figure 17: Impacts within the wetland system and immediate surroundings 16 Figure 18: Environmental Importance and Sensitivity score 16 Figure 19: Revised layout for proposed development 15

List of tables

Table 1: Rating table used to rate EIS (Rowntree, in prep) 6 Table 2: Wetland classification 11 Table 3: Geotechnical results for soil horizons confirming depositional conditions 17 Table 4: Grading and Atterberg limits test results summary (from Geotechnical Report) confirming

dominance of sand and silt 17 Table 5: Perched water table depths at time of Geotechnical investigation (2015) 18 Table 6: PES score for the valley bottom wetland 17 Table 7: Condensed summary sheet of Environmental Importance and Sensitivity score 15 Table 8: Construction Impact 1 15 Table 9: Construction Impact 2 16 Table 10: Construction Impact 3 17 Table 11: Operational Impact 1 18 Table 12: Operational Impact 2 19



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1.1 Background The report relates to the proposed development of a low-cost housing development in Nieu-Bethesda in the Karoo region of the Eastern Cape Province. The town was developed in the 19th century around a complex of springs, a river and a large wetland which are all important landscape features within an arid environment. In the ensuing decades extensive modification has occurred to all of the systems, at varying scales of magnitude. The proposed development is situated to the east of the current village, within the larger river valley currently used for irrigated grazing for livestock. A wetland study was commissioned due to the presence of medium sized valley floodplain wetland to the south and the west of the proposed development footprint. This study seeks to evaluate the current state of the wetland and examine the environmental implications of the intended development on the wetland’s functionality and integrity.

1.2 Proposed project The Client, Camdeboo Municipality (CM) proposes to develop a Greenfields area (approximately 101610m2 or 0.1 km2) situated between Nieu-Bethesda and Pienaarsig Township on the outskirts of the village. This proposed subsidy housing development will serve as the link between village and township, whereby the developable area will consist of 250 erven sized approximately 225m2 with communal public facilities sized accordingly to serve the community. The initial layout is depicted in Figure 1. After assessment of the wetland extent, present ecological state and environmental importance and sensitivity, a revised layout was proposed. The impact assessment (Section 5.4) is based on the revised development footprint.

1.3 Scope of Study The scope of work for this study include the following:

• The mapping of the wetland habitat to verify the position of the development within the wetland extent;

• A description of the wetland;

• An in-field evaluation of the present ecological state of the wetland and environmental importance and sensitivity; and

• An educated opinion of the environmental consequences of the development and suggested mitigation measures.

1 Introduction



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Figure 1: Proposed development layout



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2 Assumptions and limitations The following assumptions are applicable to this study:

• The anticipated impacts of the proposed development are based on generic issues that have arisen with similar developments;

• That the client will implement the proposed mitigation measures and recommendations as contained in this report;

• That the nature of the development will remain as described under Section 1

Th following limitations are applicable to this study:

• The conclusions and recommendations provided in this report apply only to the stipulated development. Any alternative land-use is likely to require specific management recommendations according to the anticipated impacts;

• Aquatic ecosystems vary both temporally and spatially. Once-off surveys such as this are therefore likely to miss certain ecological information, thus limiting accuracy, detail and confidence;

• It must be recognised that the study area has been substantially modified in terms of hydrological functioning and geomorphological features. From available literature and information, the entire town is in essence located on top of a historic floodplain or valley bottom wetland, with the Gats River and a major tributary now diverted around the west of the town. Based on the floodline study there is a 1:100 floodline running along the eastern side of the village, which possibly indicates the original position a river channel within the valley/floodplain setting. The geotechnical investigation also confirmed a very shallow groundwater table with soils consisting of transported silt and sand i.e. alluvial deposits. Within this altered hydrological and geomorphological setting, temporary wet areas can be noted throughout the historical floodplain. These areas are evident even within the built-up areas of the village and seems to be the result of the shallow groundwater table, an intricate (and leaking) canal system as well as flood irrigation practices. Complicating matters further is the continuous disturbance of areas suspected to be part of the temporary zone. The disturbance typically leads to the destruction of soil wetness indicators such as redox reactions and transformation (mottles). The continued disturbance is also likely to reduce or destroy hydrophytic vegetation types in the temporary zone before they can establish. Wetter conditions such as found in the seasonal and permanent zones usually restricts the survival of facultative dryland species with a more prominent occurrence of facultative wetland and obligate species. In conclusion it was found to be exceptionally difficult to confirm the exact extent of the temporary zone with even moderate levels of confidence.



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3 Methodology

3.1 Overall approach and philosophy to this study As per discussion under “limitations” under Section 2, the study area poses unique challenges in terms of the extent of the temporary zone and its level of degradation. The purpose of a wetland assessment is inter alia to determine its present ecological state as well as the ecological importance and sensitivity of the wetland (inclusive of present day use of the wetland). The aforementioned in turn feed into the process of wetland prioritisation in terms of rehabilitation, maintenance or controlled degradation. It must also be noted that the different zones of saturation within a wetland can offer varying degrees of ecological intactness as well as importance and sensitivity. The current assessment tools available do not support the separate assessment of wetland saturation zones, and such an approach would rely on the experience of the wetland specialist on a case by case basis.

The abovementioned considerations should ultimately inform an objective and balanced impact assessment of the current state and importance of the wetland in question and to which degree expected impacts on the wetland will cause a shift in its present ecological conditions as well as the ecological services offered. The aforementioned must further consider the importance of the wetland within a catchment and regional setting as well.

3.2 Wetland Delineation As mentioned the wetland habitats associated with the development site were delineated according to “A Practical Field Procedure for Identification and Delineation of Wetland and Riparian areas -Edition 1” (DWAF 2005). The boundary of the wetlands, as determined by the edge of the temporary wetness zone, as well as the seasonal and permanent wetness zones, was determined at appropriate intervals using a combination of soil and vegetation indicators. Only the wetland areas directly associated with the development site were delineated, with the remaining habitat boundaries outside the site mapped and verified at a lower resolution to place the systems into a landscape context.



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Figure 2: Cross section through a wetland, indicati ng how the soil wetness and vegetation indicators change as one moves along a gradient of decreasing wetness from the middle to the edge of the wetland (DWAF, 2005).

The soil sample points were recorded utilizing a mapping grade Global Positioning System (GPS). The subsequent information was assimilated to produce a Geographical Information System (GIS) spatial database of the wetland area.

A classification system has been proposed, and widely accepted, that recognises the link between wetland types to water and their geomorphological position in the landscape, commonly referred to as the hydrogeomorphic approach. This approach is based on three fundamental factors that influence how wetlands function, namely:

• Position in the landscape (geomorphic setting);

• Water source (hydrology); and

• The flow and fluctuation of the water once in the wetland (hydrodynamics).

The HGM approach classifies wetlands based on their differences in functioning, and importantly defines the functions that each class of wetland is likely to perform. The approach has been modified for use locally by Marneweck and Batchelor (2002) and Kotze, Marneweck, Batchelor, Lindley and Collins (2004), and it has been proposed as the basis of inland wetland classifications in South Africa (Ewart-Smith et al., 2006). This information has recently been collated by Ollis (2013), to form a consistent basis adopted in for wetland specialist studies in South Africa. The wetlands identified within the study site were classified and described accordingly, which highlighted the key hydrological drivers of the systems.

3.3 Wetland evaluation

3.3.1 Assess present ecological status of wetlands The following steps were used to assess the ecological status and associated impacts and threats posed to the wetland system:

• Describing the hydro-geomorphic setting of the wetland according to Kotze et al. (2008); and



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• Assessing the overall health of the wetland at a Level 2 using WET-Health. In order to improve the resolution of baseline data collection, information on impacts to vegetation and hydrology (water distribution and retention patterns) are captured at an impact unit level. This improves the accuracy of extent estimates and allows assumptions to be more clearly documented for future comparison. (Macfarlane et al., 2007).

Assess importance and sensitivity of wetlands

The importance of the wetland was assessed by considering the range of goods and services identified in the Wet-Ecoservices tool. The outcomes of the Wet-Ecoservices assessment were then used to inform an assessment of the importance and sensitivity of the wetland using the Wetland EIS assessment tool (Rowntree, in prep). The tool includes an assessment of three components:

• Biodiversity support;

• Landscape scale importance; and

• Sensitivity of the wetland to floods and water quality changes.

The maximum score for these components was taken as the importance rating for the wetland which is rated using Table 1, below.

Table 1: Rating table used to rate EIS (Rowntree, i n prep)

Rating Explanation

None, Rating = 0 Rarely sensitive to changes in water quality/hydrological regime

Low, Rating =1 One or a few elements sensitive to changes in water quality/hydrological regime

Moderate, Rating =2 Some elements sensitive to changes in water quality/hydrological regime

High, Rating =3 Many elements sensitive to changes in water quality/ hydrological regime

Very high, Rating =4 Very many elements sensitive to changes in water quality/ hydrological regime



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4 Study area and site characteristics

4.1 General description The site is located within the town of Nieu Bethesda in the Karoo region of the Eastern Cape Province. The town is situated at the confluence of three valley systems, and is dominated by a large, flat open floodplain. The dominant land-use is commercial livestock production, particularly sheep. The surrounding uplands are used for extensive livestock grazing, while the flat, fertile bottomlands consist of irrigated pastures.

The town straddles a perennial river that arises in the Sneeuberge. An intricate system of canals has been constructed to feed water-tanks within the town and for flood irrigation of the grazing lands on the valley floodplain.

4.2 Geology The surrounding geology is dominated by Ecca shales and sandstones, and catchment soils are shallow. Soil storativity is low, which coupled with the steep valley slopes indicate that water is not held in the catchment for long following rainfall events. The river’s perennial flow regime indicates substantial vertical recharge throughout the catchment, likely via cracks and fissures in the underlying rock layers. The vegetation is sparse and dominated by karroid shrubs interspersed with grasses and succulents.

4.3 Climate The local climate is characterised by warm summers and cool, dry winters. Mean Annual Precipitation is approximately 381mm per annum (www.climate-data.org), with most of this occurring in Autumn. Mean Annual Evapotranspiration is high, reflecting the dry climate. Rainfall is unpredictable, highly variable and expressed as short, intense rainfall events of varying magnitude.

Figure 3: Long-term climatic data for Nieu-Bethesda (www.climate-data.org )



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4.4 Surface water The main surface water feature in the study area is the Gats River which flows in a north-south direction along the western edge of the town. It has a PES score Class D1 i.e. largely modified and is classified as an ephemeral Order 2 river. The river’s sub-catchment is classified as a Fish Support Area (FSA) for Barbus anoplus and Labeo umbratus (both IUCN Least Concern).

In terms of the NFEPA (2011) wetland dataset, only one natural channelled valley bottom wetland has been recorded in the Gats River, downstream of the town of Nieu-Bethesda. The sub-catchment is further classified as low yielding with a calculated MAR of 75 Mm3.

Figure 4: NFEPA (2011) Fish Sanctuary classificatio ns for the study area

1 Nel, J. L., A. Driver, W. Strydom, A. Maherry, C. Petersen, D. J. Roux, S. Nienaber, H. van Deventer, L. B. Smith-Adao, and L. Hill. 2011. Atlas of freshwater ecosystem priority areas in South Africa: maps to support sustainable development of water resources. Water Research Commission, Pretoria, South Africa.



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Figure 5: Wetland ins study area based on NFEPA (20 11) data

4.5 Groundwater The study area falls within the Eastern Great Karoo hydrogeological region with low to moderate yielding (0.5 – 2 ℓ/s) fractured aquifers as well as a number of low yielding (0.1 – 0.5 ℓ/s) intergranular aquifers2.

4.6 Landcover The study area’s landcover is dominated by natural vegetation cover along slopes and elevated areas while valleys and gentle slopes are used for agriculture. Nieu-Bethesda is the only urban landuse wihtin a 50 km radius.

2 Department of Water Affairs, 2010. Eastern Cape Groundwater Plan. Version 1



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Figure 6: Land cover in the immediate study area

Figure 7: Typical view of the wetland catchment, sh owing short, sparse vegetation growth, steep slopes and rocky surface



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5 Results

5.1 Wetland/site characteristics Table 2 below provides a summary of the wetland characteristics based on the 2013 Wetland Classification System3.

Table 2: Wetland classification

Level 1: Coastal or inland Inland

Level 2: Regional setting Great Karoo

Level 3: Landscape unit Valley floor

Level 4: Hydrogeomorphic unit

Floodplain*

Level 5: Hydrological regime

Inundation occurs very seldom (every 10 to 50 years), majority of wetland has very low levels of saturation. Permanent saturation occurs where the seasonal and permanent zones form a topographic low point which cuts into the underlying shallow groundwater table.

Level 6: Descriptors: i. Vegetated

ii. Herbaceous

iii. Grasses and sedges

iv. Predominantly indigenous in seasonal and permanent zones. Cultivated crops in temporary zone

* See comments below regarding HGM unit interpretatio n

The following observations were made regarding the site and wetland characteristics:

• The topography consists of a flat, broad floodplain surrounded by steep, rocky slopes. The Gats River is mostly confined to the western edge of the floodplain, cutting from west to east across the floodplain immediately before the river enters a more confined, narrow valley downstream of the floodplain.

• There is also a tributary with a moderately sized catchment area (+/- 20 km2) joining the Gats River from the north. The existing floodplain might have been partially linked to this tributary as well prior to the tributary being redirected into its current point of confluence with the Gats River.

• Based on the available literature the owner of the original farm (Uitkyk owned by B.J. Pienaar) already diverted the Gats River in the late 1880’s to drain the wetlands in the floodplain and convert the area to arable land.

• The Gats River and abovementioned tributary are now mostly confined to their channels. Thus, despite the wetland being located on a valley floor representative of an upland floodplain longitudinal zone, the hydrological and geomorphological drivers of the wetland do not conform strictly to that of a

3 Ollis, D.J., Snaddon, C.D., Job, N.M. and Mbona, N. 2013. Classification System for Wetlands and other Aquatic Ecosystems in South Africa. User Manual: Inland Systems. SANBI Biodiversity Series 22. South African National Biodiversity Institute, Pretoria



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floodplain wetland. Yet the alternative classification as a unchanneled valley bottom wetland is also problematic in that the wetland does not form part of a defined river channel with no channel inflow. As a result, the Level 4 Hydrogeomorphic Unit classification was determined as a floodplain wetland and not an unchanneled valley bottom wetland

• According to the geotechnical study done, the wetland is situated on a perched water table +/- 1.5 to 1.7m deep. The water table might however not conform strictly to the typical definition of a perched water table as it is likely linked to the alluvial strata in the floodplain associated with the original river channel alignment. Nonetheless this means that there should be substantial groundwater contributions to the wetland in terms of hydrological drivers, especially the seasonal and permanent zones which are within a topographical low point in the floodplain valley. Continuous irrigation of cultivated grazing is also likely contributing to saturated soil conditions.

• There is a substantial number of scattered seasonal and permanent zones of saturation within the larger floodplain area. It is thus difficult to draw a definitive boundary for each zone of wetness. The presence of infrastructure within the floodplain further complicates accurate delineation. For the purpose of this study, the various zones in relation to the proposed development were determined and mapped.

• There has been substantial long-term disturbance to the site, in the form of building construction, roads, gardens, river and stream modification, the excavation of irrigation canals, and cultivation. The typical soil indicators associated with saturated conditions (i.e. mottling, bleaching, gleying) are thus unlikely to be present in certain areas where the soil is regularly disturbed or impacted.

• Considerable removal of indigenous vegetation has occurred in the river valley/floodplain with land use dominated by irrigated grazing pastures and small-scale crop production.

• There is minimal infestation by alien invasive plant species.

Under natural conditions, the dominant hydrological drivers of the wetland were likely to have been:

• Periodic inundation by overbank topping of the Gats River during flood events; • Diffuse surface runoff from the surrounding steep rocky slopes during intense storm

events;

• The influx of water from two intermittently flowing streams into the northern reaches of the wetland;

• Lateral seepage from the Gats River; • Groundwater recharge from surrounding mountainous/elevated areas bordering

the floodplain; and

• Groundwater recharge from the underlying shallow alluvial water table. These drivers have been modified in the following ways:

• Surface runoff from the eastern catchment is intercepted by a cut-off drain that skirts the periphery of the township to the east of the wetland (Figure 9). This



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intercepts all runoff from the bordering eastern slopes and directs it south before discharging it into the southern portion of the wetland;

• A minor drainage line that drains into the wetland from the north-northeast has also been diverted into a canal that runs through the centre of the township. This also discharges into the southern portion of the wetland;

• Another moderately sized tributary draining towards the Gats River from the north has been canalised around the town and into the Gats River. It’s likely that this tributary contributed to significant flows onto the wider floodplain prior to be canalised and diverted;

• The Gats River channel has been widened and excavated, deactivating the floodplain and ensuring that overbank topping now only occurs in the most extreme of rainfall events, such as flash floods;

• A weir wall has been constructed in the Gats River immediately downstream of the its confluence with the tributary (see Figure 15), this is also likely to have an impact on the velocity and direction of flow during flood events; and

• The cultivated lands to the west of the wetland are flood irrigated by means of an elaborate canal system that channels water from higher up in the Gats catchment. It is likely that infiltrated irrigation water moves laterally into the wetland where it contributes to the maintenance of saturated conditions within the wetland.

The current hydrological drivers were identified as the following:

• A shallow water table supporting a temporary to seasonal zone across most of the floodplain and a seasonal and permanent zone where the floodplain landscape has a natural topographic low point along the south-southeastern edge of the floodplain

• Flood irrigation practices on the eastern half of the floodplain/valley • Lateral seepage from the Gats River which is at a topographically higher point than

the majority of the surrounding floodplain

• Occasional surface flow contributions to the seasonal and permanent zone by means of the stormwater diversion berm and canal (see Figure 15)

• Occasional surface and groundwater recharge from the surrounding hillslopes to the north and east



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Figure 8: View of the wetland from the southern edg e looking north. In the foreground is the seasonal and permanent zone wetland mosaic indicate d by the green vegetation and Juncus vegetation

Figure 9: The deep cut-off channel skirting the eas tern low-cost housing area is



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Figure 10: Weir wall in the Gats River looking west

Figure 11: Straightened and canalised tributary ups tream of its confluence with the Gats River



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Figure 12: 1m Contour map (generated from Google Ea rth elevation data via QGIS) showing the topography of the study area in spectral colour ran ge (blues depicting lower elevations)

Figure 13: Location of trail pits for Geotechnical investigation



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Table 3: Geotechnical 4 results for soil horizons confirming depositional conditions

Table 4: Grading and Atterberg limits test results summary (from Geotechnical Report) confirming dominance of sand and silt

4 Outeniqua Geotechnical Services, 2015. Phase 1 Geotechnical Site Investigation Report: Proposed Subsidy Housing Project Nieu-Bethesda, Eastern Cape Province



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Table 5: Perched water table depths at time of Geot echnical investigation (2015)

Figure 14: Trial pit 9 illustrating typical soil co nditions and perched water table


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Figure 15: Overview of study area


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5.2 Present Ecological State The wetland has been extensively modified, with the overarching result being the desiccation of the wetland habitat, its reduction in extent; and a change in the distribution of the zones of saturation within the wetland.

5.2.1 Vegetation alteration

5.2.1.1 Catchment Catchment vegetation is mostly intact. Notable transformation has however occurred along sections of the riparian zone within the upper catchment of the Gats River. The areas immediately surrounding the wetland have been almost completely transformed by medium density residential areas (including infrastructure such as roads, sports fields, wastewater treatment works, a cemetery, schools, small businesses) as well as agricultural activities (orchards, cultivated grazing).

5.2.1.2 Wetland

Only approximately 15 to 20% of vegetation within the wetland has not been transformed completely. The more intact vegetation is confined to the seasonal and permanent zones, probably because it’s too wet for other uses such as cultivation or infrastructure development.

5.2.2 Hydrological impacts

5.2.2.1 Catchment

There are various small (<5ha) to medium (5 to 25 ha) sized dams within the Gats River and its tributaries upstream of the wetland. This will likely impact on flood peaks in terms of frequency and duration. There is also an instream weir close to the town which will impact flow direction and velocity and frequency of bank overtopping.

Given the agricultural activities along the Gats River and its tributaries it can also be assumed that surface water abstraction occurs along the reaches of the river and its tributaries. There is also abstraction occurring approximately 1.5 km upstream of the weir wall (in the Gats River next to the town) to supply the town with irrigation water via a complex canal system. The off-take point for the municipal water supply is located at the weir wall and supplies a 1 Mℓ reservoir (located east of the Pienaarsig Township).

As mentioned according to available literature the owner of the original farm (Uitkyk owned by B.J. Pienaar) already diverted the Gats River in the late 1880’s to drain the wetlands in the floodplain and convert the area to arable land. A northern tributary was also straightened and diverted around the town and now discharges into the Gats River immediately upstream of the weir. A minor tributary which would’ve discharged into the eastern portion of the floodplain has also been diverted/canalised by means of a channel and now flows through the township before it discharges into seasonal/permanent zone of the wetland.

There is limited catchment hardening as the town of Nieu-Bethesda is only urban land use within the upper Gats River catchment.

5.2.2.2 Wetland

In-wetland hydrological impacts include the following:


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• The diversion of the Gats River and major tributary has resulted in a shift in hydrological drivers within the wetland with the typical drivers for floodplain wetlands such as overtopping of banks and strong lateral recharge being reduced significantly

• An unknown number of private boreholes used to irrigate erven;

• Various roads crossing the wetland impacting on later surface water movement;

• Minor impoundment in the floodplain (supplied with water from either private boreholes or the canal system);

• Flood irrigation practices within the wetland; and

• Alien invasive tree species with high water consumption potential such as blue gum and poplar trees

5.2.3 Geomorphological impacts

5.2.3.1 Catchment

In terms of sediment budget, the various instream impoundments along the upper catchment of the Gats River are likely to contribute to a reduction in sediment transport resulting in sediment trapping along the various reaches of the river. Abstraction from the river for agricultural purposes is also likely to contribute in a reduction of flow and thus the erosive and sedimentation transport capacity of the system. There are only minor potential causes of increases in sediment supply in the catchment. The main potential contributing factor is the disturbance of soil along the riparian zone for crop production/agricultural purposes. The is also evidence of minor to moderate dryland erosion and in-channel erosion within the catchment upstream of the wetland.

5.2.3.2 Wetland

In terms of sediment budget within/immediately adjacent to the wetland, the following impacts were observed:

• A reduction in sediment supply as a result of the diversion of two tributaries to the north of the wetland. Under Reference State conditions both tributaries would’ve contributed to notable sediment deposition within the floodplain.

• There are various dirt roads as well agricultural land within the wetland which is likely to lead to an increase in sediment supply.

• Vegetation cover has been reduced in the township, but the wetland is generally well vegetated, although not with indigenous/natural vegetation cover

• An embankment has been constructed at the “base” of the wetland, creating an artificial control point and sediment trap.

5.2.4 Water quality impacts

5.2.4.1 Catchment

Water quality within he catchment has been impacted by the following factors/activities:

• Increases in total suspended solids due to dryland and in-channel erosion

• Increases in total dissolved solids and major ions/salts due to irrigation and crop production along the riparian zone


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• Potential increases in nitrates and phosphates as a result of crop production and possibly livestock grazing along the riparian zone

• Potential increases bacteriological pathogens (E. coli) as a result of livestock wastes

Given the geology of the catchment and low annual rainfall, the TDS values under reference conditions would’ve been fairly high in any case and is not a source of major concern.

5.2.4.2 Wetland

Water quality within the wetland has been impacted by the following factors/activities:

• The presence of soak-away sanitation systems or pit latrines at most households (increases in nitrates, phosphates and E. coli)

• Continuous irrigation of crops (salinization/increase in TDS/major ions)

• Possible herbicide and pesticide application depending on agricultural practices

• Possible application of fertilizers depending on agricultural practices

• Livestock grazing resulting in an increase in E. coli and nutrients

• Limited urban land cover (possible increases in TDS, nutrients, E. coli, petroleum hydrocarbons and heavy metals)

5.2.5 PES score Based on the abovementioned observations, the Present Ecological State of the wetland has been rated as D i.e. largely modified.

Table 6: PES score for the valley bottom wetland

OVERALL PRESENT ECOLOGICAL STATE (PES) SCORE

Ranking Weighting Score Confidence Rating

PES Category

DRIVING PROCESSES: 100 2,3

Hydrology 1 100 2,8 3,0 D

Geomorphology 2 80 2,3 1,5 D

Water Quality 3 30 0,7 2,8 B

WETLAND LANDUSE ACTIVITIES:

80 2,2 3,0

Vegetation Alteration Score 1 100 2,2 3,0 D

Weighting needs to consider the sensitivity of the type of wetland

(e.g.: nutrient poor wetlands will be more sensitive to nutrient loading)

OVERALL SCORE: 2,3 Confidence Rating

PES % 54,7

PES Category: D 1,3


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Figure 16:Catchment impacts


Page 16

Figure 17: Impacts within the wetland system and im mediate surroundings


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5.3 Ecological importance and sensitivity Table 7 and Figure 18 below provides a summary of the EIS scores allocated to the wetland with a discussion of the direct and indirect benefits under the consecutive sections below.

Table 7: Condensed summary sheet of Environmental I mportance and Sensitivity score

Overall score Confidence rating

Flood attenuation 0,9 2,8

Streamflow regulation 0,7 2,3

Sediment trapping 1,7 2,8

Phosphate trapping 1,6 2,7

Nitrate removal 1,6 2,4

Toxicant removal 1,5 2,8

Erosion control 2,6 2,1

Carbon storage 1,3 3,0

Maintenance of biodiversity 1,1 2,7

Water supply for human use 0,9 3,1

Natural resources 2,6 2,8

Cultivated foods 2,4 3,0

Cultural significance 1,0 3,3

Tourism and recreation 0,9 2,4

Education and research 0,5 3,3

Threats 1,0 3,0

Opportunities 1,0 3,0


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Figure 18: Environmental Importance and Sensitivity score

5.3.1 Direct benefits In terms of direct benefits, the wetland has limited provisioning benefits in terms of water supply and harvestable resources. The Gats River is the main source of potable water supply, thereby reducing the importance of the wetland and the underlying associated aquifer in terms of water security. The temporary zone is currently extensively used for agricultural purposes which can be seen as a direct benefit.

In terms of maintenance of biodiversity, the temporary zone of the wetland offers very little benefit as it is completely transformed. The seasonal and permanent zones do contribute to biodiversity in terms of supporting indigenous hydrophytic vegetation and providing an aquatic environment to invertebrates and avifauna.

5.3.2 Indirect benefits In terms of regulation and supporting benefits, the wetland offers the following services:

• Flood attenuation: The seasonal and permanent zones of the wetland offers flood attenuation services in terms of the canal and diversion berm discharging into these zones. The temporary zone has limited importance in terms of flood attenuation as the Gats River and major tributary seldom discharge into the wetland (as a result of human intervention) i.e. the typical hydrological dynamics associated with a floodplain wetland have been altered substantially

• Sediment trapping: The wetland is generally well vegetated although not necessarily by indigenous/natural vegetation. As with flood attenuation the seasonal and permanent zones will assist in trapping sediment from the canal and diversion berm discharges. As the wetland is now isolated from the larger floodplain and associated river, its sediment trapping contributions have declined significantly i.e. beneficial only in terms of the immediate area and not the catchment

• Nitrate and phosphate assimilation: The wetland and upper catchment are subject to additional nitrate and phosphate inputs. As the wetland is now isolated from the


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larger floodplain and associated river, its nutrient assimilation contributions have declined significantly i.e. beneficial only in terms of the immediate area and not the downstream catchment

• Erosion control: The wetland is generally well vegetated and will contribute to erosion control as a result of sediment trapping and contribution to lower flow velocities. As the wetland is now isolated from the larger floodplain and associated river, its erosion prevention services have declined significantly i.e. beneficial only in terms of the immediate area and not the downstream catchment. It does however definitely assist to prevent erosion due to stormwater/surface flow discharges into the seasonal and permanent zones.

5.4 Impact assessment

5.4.1 Details of proposed mitigation measures In order to give context to the ratings assigned to post-mitigation impacts, please refer to the proposed alternative layout on the next page (Figure 19). Note that the impact assessment is based on the revised layout and not the original layout. The original layout (REV9) is considered to be fatally flawed in terms of the extent of wetland, and specifically the seasonal and permanent zones, impacted.

5.4.2 Construction phase One of the primary impacts of concern during construction is the permanent loss of a portion of the temporary zone of the wetland. As discussed earlier in this document, the entire town of Nieu-Bethesda is situated on a floodplain with a shallow groundwater table. The floodplain formed part of the Gats River’s original flow path and according to available information in order to develop the area, the river was diverted along the western edge of the valley, draining the wetlands associated with the original flow path. A major tributary to the north of the floodplain/wetland was also diverted towards the now confined Gats River, thereby essentially limiting any notable surface flow contributions to the floodplain and wetland.

In terms of the current hydrology of the system, the system’s level of saturation seems to be supported primarily by the shallow groundwater table, possible lateral seepage from the Gats River and then flood irrigation practices.

Given the low average rainfall in the area and very small catchment of the on minor tributary’s flow which is diverted to the seasonal/permanent zones of the wetland, it can be assumed with a high degree of confidence that natural surface recharge currently plays a very minor role in maintaining saturated conditions within the wetland.

The portion to be lost, based on the revised layout, is approximately 5 ha along the eastern edge of the temporary zone (+/- 11 % of the total wetland area). The footprint of the proposed infrastructure within the temporary zone will not impede or reduce water recharges to the seasonal and permanent zones i.e. it is highly unlikely to cause a change in the hydrological drivers sustaining the seasonal and permanent zones. The loss of this portion of the temporary zone is thus likely to have a negligible impact in terms of the hydrological functioning of the more intact seasonal and permanent zones.

The one hydrological impact that will occur due to the proposed development will be a reduction in the buffer capacity of the temporary zone in relation to the protection of the remainder of the temporary zone as well as seasonal and permanent zones. The remaining buffer width will be approximately 150m, which exceeds the recommended buffer width


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Figure 19: Revised layout for proposed development


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calculated by means of the 2014 WRC Buffer Zone Tool5 by an order of a magnitude. Given that the buffer area is fairly densely vegetated with grass species, the functionality of the temporary zone in terms of overall buffer capacity is unlikely to be of any significance.

In terms of biodiversity maintenance functions, the affected portion of the temporary zone offers little, if any, support or services in terms of the maintenance of biodiversity. Table 8 to Table 10 summarise the construction impacts foreseen for the proposed development with specific relevance to the wetland in question.

Table 8: Construction Impact 1

Project phase Construction Impact Partial loss of temporary zone Description of impact

The construction of the housing infrastructure will permanently transform a section of the temporary zone to non -wetland conditions

Mitigatability Low Mitigation does not exist; or mitigation will slightly reduce the significance of impacts

Potential mitigation

• Ensure land uses which are completely transformative are situated towards the outer edge of the temporary zone;

• Ensure stormwater retention structures are in place to assist with the delayed and diffuse discharge of runoff into the seasonal and permanent zone;

• Ensure that there is an appropriate/sufficient buffer consisting of the remainder of the temporary zone;

• Do not alter the groundwater and lateral flow recharge and dynamic associated with the larger floodplain

• Fence off the seasonal and permanent zone to avoid further disturbance and increase the wetland services provided by these zones

Assessment Without mitigation With mitigation Nature Negative Negative Duration Permanent Impact may be

permanent, or in excess of 20 years

Permanent Impact may be permanent, or in excess of 20 years

Extent Limited Limited to the site and its immediate surroundings

Limited Limited to the site and its immediate surroundings

Intensity Low Natural and/ or social functions and/ or processes are somewhat altered

Very low Natural and/ or social functions and/ or processes are slightly altered

Probability Certain / definite

There are sound scientific reasons to expect that the impact will definitely occur

Certain / definite

There are sound scientific reasons to expect that the impact will definitely occur

Confidence High Substantive supportive data exists to verify the assessment

High Substantive supportive data exists to verify the assessment

Reversibility Low The affected environment will not be able to recover from the impact = permanently modified

Low The affected environment will not be able to recover from the = permanently modified

5 Macfarlane, D.M. Bredin, I.P. Adams, J.B., M.M. Zungu, Bate, G.C. and Dickens, C.W.S. 2014. Buffer zone tool for the determination of aquatic impact buffers and additional setback requirements for wetland ecosystems. Version 1.0. Prepared for the Water Research Commission, Pretoria.


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Resource irreplaceability

Medium The resource is damaged irreparably but is represented elsewhere

Low The resource is not damaged irreparably or is not scarce

Significance Moderate - negative Moderate - negative Comment on significance

The temporary zone has been significantly transformed, offering limited direct and indirect services. As the temporary zone stretches across large parts of the floodplain, the loss of this portion of the temporary zone is of limited significance. As a result of the system's hydrological drivers being linked strongly to a shallow water table and lateral seepage from the Gats River, the loss of a portion of the temporary zone is also unlikely to impact on the hydrological mechanisms which sustains the seasonal and permanent zones

Cumulative impacts

The temporary zone associated with the floodplain has been modified and transformed significantly. This development will add to the cumulative reduction in the extent of the temporary zone


Project phase Construction Impact Increase in sediment loads Description of impact

Removal of vegetation and disturbance of soil will result in elevated sediment loads in surface runoff

Mitigatability Medium Mitigation exists and will notably reduce significance of impacts Potential mitigation

• Ensure an adequate buffer zone is maintained around seasonal and permanent zone;

• Limit vegetation clearance; • Erodible stockpiles should be placed away from sensitive receptors; • Stockpiles placed away from areas of high volume surface flows; • Revegetation as soon as construction has been completed

Assessment Without mitigation With mitigation Nature Negative Negative Duration Short term impact will last between 1

and 5 years Brief Impact will not last

longer than 1 year



Intensity Very low Natural and/ or social functions and/ or processes are slightly altered


Probability Almost certain / Highly probable

It is most likely that the impact will occur

Almost certain / Highly probable


Confidence Medium Determination is based on common sense and general knowledge

Medium Determination is based on common sense and general knowledge

Reversibility Medium The affected environment will only recover from the impact with significant intervention

High The affected environmental will be able to recover from the impact




Significance Minor - negative Minor - negative


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Comment on significance

The wetland is already absorbing increased sediment loads. The impact should be minor with the implementation of mitigation measures such as an adequate buffer zone around the seasonal and permanent zones.

Cumulative impacts


Project phase Construction Impact Decline in water quality as a result of hydr ocarbon or other hazardous

substance spillages Description of impact

Limited quantities of hazardous mat erials/products will be used during construction. These pose a pollution risk if not ma naged properly

Mitigatability High Mitigation exists and will considerably reduce the significance of impacts

Potential mitigation

• Store hazardous materials outside wetland in a dedicated area (weather proof) in appropriate containers;

• Dispense product using appropriate equipment; • Ensure proper storage and disposal of containers used for storage of

hazardous product; • Have appropriate clean-up equipment e.g. Spill kit; • Ensure plant/vehicles are parked outside wetland area at the site camp

when not in use

Assessment Without mitigation With mitigation Nature Negative Negative Duration Short term impact will last between 1

and 5 years Brief Impact will not last longer

than 1 year Extent Limited Limited to the site and its

immediate surroundings Limited Limited to the site and its

immediate surroundings Intensity Very low Natural and/ or social

functions and/ or processes are slightly altered


Probability Probable The impact has occurred here or elsewhere and could therefore occur

Probable The impact has occurred here or elsewhere and could therefore occur


Low Judgement is based on intuition

Reversibility Low The affected environment will not be able to recover from the impact - permanently modified

Medium The affected environment will only recover from the impact with significant intervention




Significance Negligible - negative Negligible - negative Comment on significance

Cumulative impacts

5.4.3 Operational phase The expected operational impacts will not be new in terms of the wetland’s minor active surface catchment as the land uses and related impacts already occur. The proposed development will be an extension of the existing low-cost housing to the east of the wetland. Two impacts


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which will cumulatively increase in terms of the development are the decrease in surface water infiltration and potential additional influx of pollutants into the wetland system.

The first impact is considered to be of minor negative significance. As discussed under previous sections, the hydrology of the wetland is mostly driven by groundwater recharge and not surface recharge. The minor reduction in immediate infiltration can easily be mitigated by the collection, retention and controlled release of stormwater generated on the new hardened surfaces. The area of stormwater generation is also very flat with minimal erosive capacity.

In terms of the influx of additional pollutants, the risk is considered minimal given the type of development. No high-risk activities (e.g. filling stations, intensive agriculture, waste storage/disposal etc.) are planned for the development and only a marginal increase in pollutants is expected. Table 11 and Table 12 summarises the two impacts discussed.

Table 11: Operational Impact 1

Project phase Operation

Impact Decrease in surface water infiltration and i ncrease in surface water flows across impermeable surfaces (i.e. increase in erosi ve capacity)

Description of impact

The hardened surfaces associated with the built-up portions of the proposed project will result in a decrease in the i nfiltration of surface water. It will also result in an increase in the volume an d velocity of surface water

discharge to the surrounding environment Mitigatability Medium Mitigation exists and will notably reduce significance of impacts Potential mitigation

Construct suitably designed stormwater retention structures to gradually release collected runoff into the wetland

Assessment Without mitigation With mitigation Nature Negative Negative Duration Permanent Impact may be

permanent, or in excess of 20 years

Permanent Impact may be permanent, or in excess of 20 years


Very limited Limited to specific isolated parts of the site

Intensity Very low Natural and/ or social functions and/ or processes are slightly altered


Probability Almost certain / Highly probable


Almost certain / Highly probable


Confi dence Medium Determination is based on common sense and general knowledge



High The affected environmental will be able to recover from the impact




Significance Minor - negative Minor - negative Comment on significance

As the saturation of wetland system is primarily a result of a shallow water table, lateral groundwater migration and flood irrigation, the replacement of diffuse surface water infiltration with controlled point releases should have a negligible impact on the rest of the wetland system.

Cumulative impacts

The proposed development will add to the cumulative percentage of hardened surfaces within the wetland's catchment.


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Table 12: Operational Impact 2

Project phase Operation Impact Influx of pollutants such as pesticides, her bicides, hydrocarbons, nutrients

and pathogens into the wetland Description of impact

An urban area inherently impacts on the water quali ty of the surrounding receiving water resources. The significance of this impact is strongly linked

to the type of urban land use e.g. low density resi dential versus high density industrial or commercial. The nature of the proposed development poses a fairly low pollution risk as there are no h igh-risk activities e.g. fuel

stations, factories, waste storage or disposal etc. Mitigatability Medium Mitigation exists and will notably reduce significance of impacts Potential mitigation

• Ensure that potential polluting activities are located in low risk areas and have sufficient pollution prevention measures in place

• Provide training for use of agricultural land to reduce potential pollutant sources, ensure waste management is done effectively

Assessment Without mitigation With mitigation Nature Negative Negative Duration On-going Impact will last between 15

and 20 years On-going Impact will last between

15 and 20 years



Intensity Low Natural and/ or social functions and/ or processes are somewhat altered


Probability Probable The impact has occurred here or elsewhere and could therefore occur

Probable The impact has occurred here or elsewhere and could therefore occur




Medium The affected environment will only recover from the impact with significant intervention




Significance Minor - negative Minor - negative Comment on significance

Cumulative impacts

The proposed development will add to the cumulative impact on water quality associated with the town of Nieu-Bethesda and the Pienaarsig township


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6 Summarising discussion of findings The wetland system in question is quite complicated in terms of functioning and extent due to the extensive modification of its hydrological drivers and significant transformation of wetland habitat. From the limited information available regarding the history of Nieu-Bethesda it is evident that the Gats River was diverted in order to drain the floodplain and allow for cultivation along the floodplain. The town has also subsequently been established within the historical floodplain. The aforementioned presence of a floodplain is confirmed by the soil characteristics (sandy loam and silt) and the presence of a shallow (<1.5m) water table.

The historical hydrological drivers such as lateral recharge, bank overtopping and sediment deposition have thus been replaced by predominantly a shallow water table and flood irrigation practices. This has resulted in the desiccation of large portions of the now temporary zone of the wetland. The delineation of the extent of the temporary zone is also further complicated by significant soil disturbance and transformation of vegetation cover which resulted in the destruction of soil form and wetness indicators as well as vegetation type indicators. The only remaining criteria to confirm the extent of the temporary zone is thus Terrain Unit indicators (used in combination with available aerial and satellite imagery). The seasonal and permanent zones of the wetland are more easily identifiable by means of typical wetland indicators and could be determined with a higher degree of certainty.

In terms of PES, the temporary zone of the wetland has been completely transformed while the seasonal and permanent zones are impacted but not transformed with ecological functioning mostly intact. The wetland system as a whole has a PES Category D i.e. Largely Modified mostly as a result of major impacts on the hydrological functioning of the system combined with significant transformation of vegetation. It should be noted that the wetland system is now mostly isolated from the Gats River and one of its major tributary’s catchments. Within wetland impacts were thus allocated the maximum weighting during PES scoring of the various drivers and land uses.

At present the desiccated, mostly terrestrial, temporary zone offers very little, if any, ecological services in terms of wetland habitat, with its main function being to buffer the seasonal and permanent zones from further impacts and degradation. The seasonal and permanent zones, although small in comparison to the temporary zone, are thus the main areas of concern in terms of maintaining ecological functioning and wetland services.

In terms of the proposed development the initial layout and extent as depicted in Figure 1 was found to be unacceptable/fatally flawed due to the encroachment on the seasonal zone and the extent of the temporary zone lost. Based on the 1:50 year floodline data and zone delineation of the wetland, a revised layout was thus proposed (Figure 19) and the impact assessment and mitigation measures were done based on the revised layout and not the original layout.

In terms of identified impacts, it was found that the only impact of potential significance would be the loss of a portion of the temporary zone. Given the transformed nature of the temporary zone, combined with its low ecological importance and sensitivity, a loss of a portion of the temporary zone was scored as having a moderate negative impact, with the significance score pushed up due to the permanent nature of the impact. The revised layout however allows for the maintenance of habitat connectivity while allowing a sufficient buffer (150m which is an order of a magnitude more than the buffer calculated using the 2014 Buffer zone model) between the proposed development and the seasonal zone.


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In terms of operational or permanent impacts, the decrease of surface water infiltration in the temporary zone and immediate catchment was identified as a negative impact of minor significance. The low significance can be attributed to the following:

• The main hydrological drivers in the wetland system are groundwater related and not surface water

• The extent of the new hardened surfaces is not likely to impact the maintenance of saturated conditions within the wetland

• The impact can easily be mitigated by means of a retention and controlled discharge stormwater system

The other operational impact (low significance) which was identified is the influx of additional pollutants into the wetland system. This impact’s low significance score can be attributed to the nature of the development (i.e. low pollutant generation and release risk) and the fact that similar land uses already occur within the wetland and its immediate catchment with limited cumulative potential.

To summarise, the proposed development (based on the new layout) is unlikely to impact negatively on the seasonal and permanent zones of the wetland, with the potential of improving the ecological functioning and services offered, should the recommended mitigation measures be implemented. The loss of a portion of the mostly desiccated and transformed temporary zone, while not ideal, can be justified as the development will provide housing to a vulnerable portion of the population.

Based on the principles and criteria applied to prioritise wetlands for rehabilitation6, specifically Box 2 (pg. 33), the wetland in question is considered to be of low priority to rehabilitate. Reasons for the aforementioned include:

• While a wetland a semi-arid setting is unusual, the specific wetland in question is not rare

• It will be extremely costly and disruptive to reinstate the original hydrological drivers. Doing this will also endanger the residents of Nieu-Bethesda who are living on the historical floodplain. It is further unlikely that artificial reinstatement of the hydrological drivers will result in a stable geomorphological setting representative of the historical conditions

• The wetland is in a largely modified condition and offers few services. The section of the temporary zone which will be lost will not result in the decline of the PES or EIS of the more important seasonal and permanent zones

• The wetland has been mostly isolated from its catchment and offers few services beyond its immediate extent

• There is no specific willingness or capacity for local involvement in rehabilitation efforts

6 Rountree MW, Thompson M, Kotze DC, Batchelor AL, and Marneweck, GC, 2008. WET-Prioritise: Guidelines for prioritising wetlands at national, regional and local scales. WRC Report No. TT 337/08. Water Research Commission, Pretoria.


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7 Recommendations It is recommended that the revised layout as per Figure 19 be approved. Apart from the mitigation measures as per Table 8 to Table 12, the following specific actions are also recommended:

• Erven 49 to 56 and 77 to 81 should be excluded from the development footprint.

• A fence (5/6 strand wire) should be erected around the abovementioned erven to assist in the preservation of the seasonal and permanent zones and to potentially increase ecological integrity and functioning as well as ecological services offered

• Current land uses (cultivated grazing) within the 1:50 year floodline can continue on the premise that there will not be a change in the intensity of cultivation or type of crops cultivated.

• The development plan should include a stormwater management plan with appropriately sized stormwater retention and controlled discharge structures. All stormwater will be drained to the south of the development for release into the wetland system. The plan is to be approved by both the wetland specialist and DWS

• The development may only be used for the purposes indicated i.e. medium density low cost housing

• As part of the water use licence conditions it is recommended that biannual monitoring inspections are carried out by a wetland specialist for at least 5 years post-construction to confirm the efficiency of the mitigation measures in maintaining the seasonal and permanent zones.


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8 References

Department of Water Affairs and Forestry, 2005. A Practical Field Procedure for Identification and Delineation of Wetland and Riparian areas. Edition 1, September 2005. DWAF, Pretoria. Department of Water Affairs, 2010. Eastern Cape Groundwater Plan. Version 1 Kotze, D.C., Marneweck, G.C., Batchelor, A.L., Lindley, D.S. and Collins, N.B., 2009. Wet-Ecoservices: A technique for rapidly assessing ecosystem services supplied by wetlands. Water Research Commission Report. Macfarlane DM, Kotze DC, Ellery WN, Walters D, Koopman V, Goodman P and Goge C. 2007. WET-Health: A technique for rapidly assessing wetland health. WRC Report No TT 340/08, Water Research Commission, Pretoria

Macfarlane, D.M. Bredin, I.P. Adams, J.B., M.M. Zungu, Bate, G.C. and Dickens, C.W.S. 2014. Buffer zone tool for the determination of aquatic impact buffers and additional setback requirements for wetland ecosystems. Version 1.0. Prepared for the Water Research Commission, Pretoria Nel, J. L., A. Driver, W. Strydom, A. Maherry, C. Petersen, D. J. Roux, S. Nienaber, H. van Deventer, L. B. Smith-Adao, and L. Hill. 2011. Atlas of freshwater ecosystem priority areas in South Africa: maps to support sustainable development of water resources. Water Research Commission, Pretoria, South Africa. Ollis, D.J., Snaddon, C.D., Job. N.M. and Mbona, M., 2013.Classification system for wetlands and other aquatic ecosystems in South Africa. User manual: Inland systems. SANBI Biodiversity Series 22. South African National Biodiversity Institute, Pretoria. Outeniqua Geotechnical Services, 2015. Phase 1 Geotechnical Site Investigation Report: Proposed Subsidy Housing Project Nieu-Bethesda, Eastern Cape Province

Rountree MW, Thompson M, Kotze DC, Batchelor AL, and Marneweck, GC, 2008. WET-Prioritise: Guidelines for prioritising wetlands at national, regional and local scales. WRC Report No. TT 337/08. Water Research Commission, Pretoria.

.


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Appendix A - EIS Summary sheet with calculated scor es Wetland name/reference number 1

Score Confidence rating

Additional notes

Flood attenuation

Effectiveness of the wetland

Size of wetland relative to catchment 0 3 Slope of wetland 4 3 Surface roughness of wetland 3 3 Depressions 0 3 Frequency with which stromflows spread across the wetland 1 3 Sinuosity of the stream channel 0 3 Representation of different hydrological zones 2 3 Score for effectiveness: 1,4 3,0 Opportunity for attenuating floods

Average slope of the wetland's catchment 0 3 Inherent runoff potential of soils in catchment 1 2 Contribution of catchment land-uses to changing runoff intensity from the natural condition

0 2

Rainfall intensity 1 3 Extent of floodable property downstream 0 2 Score for opportunity: 0,4 2,4 Overall score/rating for flood attenuation 0,9 2,8

Streamflow regulation

Link to the stream network 0 4 Representation of different hydrological zones 2 3 Presence of fibrous peat or unconsolidated sediments below floating marsh

0 1

Reduction in evapotranspiration through frosting back of the wetland vegetation

2 1

HGM unit occurs on underlying geology with strong surface-groundwater linkages

0 3

Presence of any important wetlands or aquatic systems downstream

0 2

Overall score/rating for streamflow aumentation 0,66667

2,3

Sediment trapping


Effectiveness in attenuating floods 1,4 3,0 Direct evidence of sediment deposition 4 3 Score for effectiveness: 2,7142

9 3,0

Opportunity

Extent to which dams are reducing the input of sediment 2 3 Extent of sediment sources delivering sediment to the HGM unit

0 3

Presence of any important wetlands or aquatic systems downstream

0 2

Score for opportunity: 0,66667

2,666667

Overall score/rating for sediment trapping 1,7 2,8


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Phosphate trapping


Effectiveness of trapping sediment 2,7 3,0 Pattern of low flows within the wetland 4 3 Extent of vegetation cover 3 3 Application of fertilizer/biocides directly in the HGM unit 3 2 Score for effectiveness: 3,2 2,8 Opportunity

Extent of sediment sources 0 3 Extent of other potential sources - point source 0 3 Presence of any important wetlands or aquatic systems downstream

0 2

Score for opportunity: 0 2,666667 Overall score/rating for phosphate trapping 1,6 2,7

1,6

Nitrate removal

Effectiveness

Hydrological zonation 2 3 Pattern of low flows 4 3 Extent of vegetation cover 3 3 Contribution of sub-surface water inputs relative to surface water inputs

4 2

Application of fertilizer/biocides directly in the HGM unit 3 2 Score for effectiveness: 3,2 2,6 Opportunity

Extent of nitrate sources in the HGM unit's catchment 0 2 Presence of any important wetlands or aquatic systems downstream

0 2

Score for opportunity: 0 2 Overall score/rating for nitrate removal 1,6 2,4

Toxicant removal

Effectiveness

Hydrological zonation 2 3 Pattern of low flows 4 3 Extent of vegetation cover 3 3 Effectiveness in trapping sediment 2,7 3,0 Application of fertilizer/biocides directly in the HGM unit 3 2 Score for effectiveness: 2,9 2,8 Opportunity

Extent of sediment sources 0 3 Extent of toxicant sources 0 3 Presence of any important wetlands or aquatic systems downstream

0 2

Score for effectiveness: 0 2,666667 Overall score/rating for toxicant removal 1,5 2,8

Erosion control

Effectiveness

Direct evidence of erosion 4 2 Extent of vegetation cover 3 3 Surface roughness 3 3 Level of soil disturbance in wetland 2 2 Score for effectiveness: 3,0 2,5 Opportunity


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Slope of wetland 4 3 Erodibility of the soil 2 2 Runoff intensity from the wetland's catchment 0,5 0 Score for opportunity: 2,2 1,7 Overall score/rating for erosion control 2,6 2,1

Carbon storage

Hydrological zones 2 3 Abundance of peat 0 4 Level of soil disturbance in wetland 2 2 Overall score/rating for carbon storage 1,3 3,0

Biodiversity maintenance

Noteworthiness

HGM unit is of a rare type or is of a wetland type or vegetation type subjected to a high level of cumulative loss

0 3

Level of cumulative loss of wetlands in the overall catchment 1 3 Red Data species or suitable habitat for Red Data species 0 2 Level of significance of other special natural features 1 2 Score for noteworthiness: 0,5 2,5 Extent of buffer around wetland 0 3 Connectivity of wetland in landscape 2 3 Alteration of hydrological regime 0 2,0 Alteration of sediment regime 2 2,666667 Alteration of nutrient/toxicant regime 3 2,666667 Complete removal of indigenous vegetation 0 3 Invasive and pioneers species encroachment 3 3 Presence of hazardous/restrictive barriers 4 3 Score for integrity: 1,8 2,791667 Overall score/rating for maintenance of biodiversit y 1,1 2,7

1,1

Water supply

Hydrological zones 2 3 Importance for streamflow augmentation 0,7 2,3 Current use for agricultural purposes 2 3 Current use for domestic purposes 1 3 Number of households 0 4 Substitutability of wetland water source 0 3 Overall score/rating for water supply 0,9 3,1

Provision of harvestable natural resources

Total number of resources 3 3 Location in rural communal area 4 3 Level of poverty 2 3 Number of households depending on wetland 3 2 Substitutability of the wetland resources 1 3 Overall score/rating for source of goods /resources 2,6 2,8

Provision of cultivated foods

Total number of different crops cultivated in the HGM unit 3 3 Location in rural communal area 4 3 Level of poverty 2 3 Number of households who depend on the crops cultivated in the HGM unit

2 3

Substitutability of the crops cultivated in the wetland 1 3


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Overall score/rating for source of goods /resources 2,4 3,0

Cultural significance

Registered SAHRA site 0 4 Location in a communal rural area 4 3 Known cultural practices 0 3 Known taboos/beliefs 0 3 Overall score/rating for socio -cultural significance 1,0 3,3

Tourism and recreation

Scenic beauty of the HGM unit 0 3 Presence of "charismatic" species 0 3 Currently used 0 2 Suitable locations for facilities 3 2 Location within a tourism route 2 2 Recreational hunting and fishing and birding opportunities 1 3 Extent of open water 0 3 Overall score/rating for tourism and recreation 0,9 2,4

Education and research

Currently used 0 4 Reference site suitability 0 3 Existing long-term research & data collected 0 3 Accessibility 2 3 Overall score/rating for education and research 0,5 3,3

Level of threats 1 3 Level of opportunities 1 3

Appendix B – EIS detailed assessment

R=Data may be available through desktop investigation but is likely to be revised/refined in the field

O=Data should be obtained in the office through desktop investigation prior to the field assessment

Date of assessment

2018 Name/s of assessors

M. Lowies

Details of owner/authority O Aurecon

Location (Latitude; Longitude) O 31°51'59.65"S; 24°33'30.05"E

Wetland name O Nieu-Bethesda Hydro-geomorphic setting of wetland

O F=Floodplain, VC=Valley bottom with channel, V=Valley bottom without channel, HW=Hillslope seepage feeding a water course, H=Hillslope seepage not feeding a watercourse, D=Depression

F

Size (hectares)

44 3

0 1 2 3 4 Score Confidence rating

HGM unit's CATCHMENT

Average slope of the HGM unit's catchment (Box 4.1h)

D <3% 3-5% 6-8% 9-11% >11% 0 3

Inherent runoff potential of the soils in the HGM unit's catchment (Box 4.1i)

O Low Mod low Mod high High 1 2

Contribution of catchment land-uses to changing runoff intensity from the natural condition (Box 4.1j)

R Decrease Negligible effect

Slight increase Moderate increase

Marked increase

0 2

Rainfall intensity (Box 4.1k) O Low (Zone I)

Moderately low (Zone II)

Mod. high (Zone III)

High (Zone IV)

1 3

Extent to which dams are reducing the input of sediment to the HGM unit (Box 4.3c)

R High Mod high Intermediate Mod low Low 2 3

Extent of sediment sources delivering sediment to the HGM unit (box 4.3d)

R Low Mod low Intermediate Mod high High 0 3

Extent of other potential sources of phosphates in the HGM unit's catchment (4.4e)


Extent of nitrate sources in the HGM unit's catchment (Box 4.5d)


Extent of toxicant sources in the HGM unit's catchment (Box 4.6b)


HGM unit

Size of HGM unit relative to the HGM unit's catchment (4.1a)

O <1% 1%-2% 3-5% 6-10% >10% 0 3

Slope of the HGM unit (%) (Box 4.1b)

O >5% 2-5% 1-1.9% 0.5-0.9% <0.5% 4 3

Surface roughness of HGM unit (Box 4.1c)

Low Mod. low Mod. high High 3 3

Depressions (Box 4.1d) R None Present but few or remain permanently filled close to capacity

Intermediate Moderately abundant

Abundant 0 3

Frequency with which stormflows are spread across the HGM unit (Box 4.1 e)

Never Occasionally

but less frequently than every 5 years

1 to 5 year frequency

More than once a year

1 3

Sinuosity of the stream channel (Box 4.1f)

R Low Moderately low

Intermediate Mod. high High 0 3

Representation of different hydrological zones (Box 4.1g)

R Permanent & seasonal zones lacking (i.e. only the temporary zone present)

Seasonal zone present but permanent zone absent

Permanent & seasonal zones both present but collectively <30%

Seasonal & permanent zone both present & collectively 30-60%

Seasonal & permanent zone both present & collectively >60% of total HGM unit area

2 3

Link to the stream network (Box 4.2a)

R No link (i.e. hydrologically isolated)

Linked to the stream system

0 4

Presence of fibrous peat or unconsolidated sediments below a floating marsh (Box 4.2c)

R Absent Present but limited in extent/depth

Moderately abundant

Extensive and relatively deep (>1.5 m)

0 1

Reduction in evapotranspiration through frosting back of the wetland vegetation (box 4.2d)

R Low Moderately low

Intermediate Moderately high High 2 1

HGM unit occurs on underlying geology with strong surface-groundwater linkages (Box 4.2e)

O No Underlying geology quartzite

Underlying geology sanstone

Underlying geology dolomite

0 3

Direct evidence of sediment deposition in the HGM unit (Box 4.3b)

Low Mod low 2 Mod high High 4 3

Flow patterns of low flows within the wetland (Box 4.4b)

R Strongly channelled

Moderately channelled

Intermediate Moderately diffuse

Very diffuse 4 3

Extent of vegetation cover in the HGM unit (Box 4.4c)


Contribution of sub-surface water inputs relative to surface water inputs (Box 4.5c)

R Low (<10%)

Moderately low (10-20%)

Intermediate (20-35%)

Moderately high (36-50%)

High (>50%) 4 2

Application of fertilizers/biocides in the HGM unit (Box 4.4d)

High Mod high Intermediate Mod low Low 3 2

Direct evidence of erosion (Box 4.7a)


Current level of physical disturbance of the soil in the HGM unit (Box 4.7d)


Erodibility of the soil in the HGM unit (box 4.7e)

O Low Mod low Intermediate Mod high High 2 2

Abundance of peat (Box 4.8b)

Absent Present but

limited in extent/depth

Intermediate Moderately abundant

Extensive and relatively deep (>0.5 m)

0 4

HGM unit is of a rare type or is of a wetland type or vegetation type subjected to a high level of cumulative loss (Box 4.9a)

O No Yes 0 3

0 3

Red Data species or suitable habitat for Red Data species (Box 4.9c)

R No Yes 0 2

Level of significance of other special natural features (Box 4.9d)

R None Mod low Intermediate Mod high High 1 2

Alteration of hydrological regime (Box 4.9g)

R High Mod high Intermediate Mod low Low/negligible

0 2

Complete removal of indigenous vegetation (Box 4.9j)

R >50% 25-50% 5-25% 1-5% <1% 0 3

Invasive and pioneers species encroachment (Box 4.9k)

>50% 25-50% 5-25% 1-5% <1% 3 3

Presence of hazardous/restrictive barriers (Box 4.9l)

R High Mod high Intermediate Mod low Low/negligible

4 3

Current level of use of water for agriculture or industry (Box 4.10c)

No use Mod low Intermediate Mod high High 2 3

Current level of use of water for domestic purposes (Box 4.10c)

No use Mod low Intermediate Mod high High 1 3

Number of dependent households that depend on the direct provision of water from the wetland (Box 4.10d)

None 1-2 3-4 5-6 >6 0 4

Substitutability of the water resource from the HGM unit (Box 4.10e)


Number of different resources used (box 4.11a)

None 1 2-3 >3 3 3

Is the wetland in a rural communal area? (Box 4.11b & 4.12b)

O No yes 4 3

Level of poverty in the area (Box 4.11c and 4.12c)

O Low/ negligible

Mod low Intermediate Mod high High 2 3

Number of households who depend on the natural resources in the HGM unit (Box 4.11d)

None 1 2-3 4-5 >6 3 2

Substitutability of the natural resources obtained from the wetland (4.11e)


Total number of different crops cultivated in the HGM unit (Box 4.12.a)

None 1 2-3 >3 3 3

Number of households who depend on the crops cultivated in the HGM unit (box 4.12d)

None 1 2-3 4-6 >6 2 3

Substitutability of the crops cultivated in the wetland (Box 4.12e)


Registered SAHRA site (Box 4.13a)

O No Yes 0 4

Known local cultural practices in the HGM unit (Box 4.13c)

None Historically

present but no longer practised

Present but practised to a limited extent

Present & still actively & widely practised

0 3

Known local taboos or beliefs relating to the HGM unit (Box 4.13d)

None Historically

present but no longer so

Present but held to a limited extent

Present & still actively & widely held

0 3

Scenic beauty of the HGM unit (Box 4.14a)

Low/negligible


Presence of charismatic species (Box 4.14b)

R None present

Very seldom seen

Occasionally present

Generally present

Always present

0 3

Current use for tourism or recreation (Box 4.14c)

No use Mod low use Intermediate

use Mod high use High 0 2

4. Availability of other natural areas providing similar experiences to the HGM unit (Box 4.14d)


Location within an existing tourism route (box 4.14f)

O Low/negligible


Recreational hunting and fishing and birding opportunities (Box 4.14g)

None Mod low Intermediate Mod high High 1 3

Extent of open water (box 4.14h)

R None Present, but very limited

Extent somewhat limited

Extensive 0 3

Current use for education/research purposes (Box 4.15a)

R No use Mod low Intermediate Mod high High 0 4

Reference site suitability (Box 4.15b)

Low Mod low Intermediate Mod high High 0 3

Existing data & research (Box 4.15c)

R None Mod low Intermediate detail/ time period

Mod high Comp-rehensive data over long period

0 3

Accessibility (Box 4.15d) R Very inaccessible

Moderately inaccessible

Intermediate Moderately accessible

Very accessible

2 3

DOWNSTREAM OF HGM UNIT

Extent of floodable property (Box 4.1l)

R Low/ negligible

Moderately low

Moderately high High 0 2

Presence of any important wetlands or aquatic systems downstream (Box 4.2f)

R None Intermediate importance

High importance

0 2

LANDSCAPE

Extent of buffer around wetland (4.9e)


Connectivity of wetland in landscape (Box 4.9f)


Level of cumulative loss of wetlands in overall catchment (box 4.9j)

O Low Mod low Intermediate Mod high High 1 3

THREATS & OPPORTUNITIES

Level of threat to existing ecosystem services supplied by the wetland (Table 4.16a)

Low Moderately

low Intermediate Moderately high High 1 3

Level of future opportunities for enhancing the supply of ecosystem services (Table 4.16b)

Low Moderately

low Intermediate Moderately high High 1 3

Document prepared by Aurecon South Africa (Pty) Ltd Reg No 1977/003711/07 Lion Roars Office Park Corner Heugh Road and 3rd Avenue Walmer Port Elizabeth 6070

PO Box 5328 Walmer 6065 Port Elizabeth South Africa

T F

+27 41 503 3900 +27 86 600 4037

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